Shielded ignition manifold system



March 9 E. A. ROBERTSON 2.23 .579

SHIELDED IGNITION MANIFOLD SYSTEM Original Filed Aug. 10, 1935' 4 Sheets-Sheet 1 1 INVENTOR d fade/M9 2 WW M ATTORN EY March 11', 1941. E. A. Rosita-sou 2.234.579

SHIELDED IGNITION MANIFOLD SYSTEI Original Filed Aug. 10, 1935 4 Sheets-Sheet 2 INVENITOR M Z/Fawe ATTORNEY March 11, 1941. 5 ROBERTSON 2,234,579

SHIEL I JED IGNITION MANIFOLD SYSTEII Original Filed Aug. 10, 1935 4 Sheets Sheet 3 INVENTOR ydmw ATTORNEY March s. A. ROBERTSON SHIELDED IGNITION MANI FOLD SYSTEII 1935 4 Sheets-Sheqf. 4

Original Filed Aug l0 Patented M... 11, 1941 2,234,519 r summon IGNITION MANIFOLD SYSTEM Edwin A. Robertson, S andusky, Ohio, assignor, by

mesne assignments, to

Bendix Aviation Corporation, South Bend, Ind., a corporation of Dela- Original application August 10, 1935, Serial No.

35,683. Divided and this 1940, Serial No. 336,920

6 Claims.

This invention relates to ignition manifolds for internal combustion .motors and has for a general object the provision of improvements in this art.

More particularly, the invention relates to a manifold .of the pull-in type which is shielded to prevent disturbance with radio reception .by stray currents from the ignition wires housed therein.

The present application is a division of my copending application, Serial No. 35,683, flled -August 10, 1935, for Shielded ignition manifold system.

Among the more specific objects of the invention are the provision of a manifold which can'be' readily assembled on a motor, for example, on an airship; where space, about the motor is very limited; which permits the insulated ignition wires to be pulled in ea'sily and without injury to the insulating covering; which includes improved flexible sections which will hold their cross-sectional shape even .when bent and preventthe opening up of'braided metal shielding placed thereon; and" which in other respects constitutes an advance in the art.

The invention may be more readily understood by reference to the accompanying drawings of an illustrative embodiment thereof wherein: 1 1' Fig. l'is a front end'elevatiori of a radial motor equipped with a manifold embodying the present invention;

Fig. 2' is a rear elevation of the same;

Fig. 3 is a side elevation;

Fig. 4 is a partial top plan view;

Fig. 5 is a section, partly in elevation taken on the line 5-5 of Fig. 6;

Fig. 6 is a section taken approximately on ,the line 6-4 of Fig. 3;

' Fig. 'l is a section taken Fig. 6; o

Fig. 8 is an enlarged section, partly in elevation, of one end of'a flexlbletrunk member; and

Fig. 9 is a similar-view of a flexible branch member.

Referring to the drawings, there is shown in pale broken lines in Fig. 1 a motor 20 on which -the manifold is adapted to be mounted. A

radial motor is selected for illustration because a radial motor normally offers the most serious problems in manifold design. However, the in-.

on the line 15-1 of vention is intended for various types of motors and various types ofvehicles. On the motor, also shown in pale broken lines (Fig. 2) there a are shown two magnetos II and :2 which are conventionally emplouod' for furnlming current shell of the fitting 35 where they will not inand the conductora'it may be, desirable to lineapplication May 24,

to the spark plugs on the front and back sides of the motor respectively. V f

The manifold assembly-sometimes referred to as harness-is shown in full lines. It comprises some rigid sections and some flexible sections. Herein there are shown the curved rigid trunk'sections 23, 24 on the front united by a T-coupling 25and the curved rigid sections 26, f 21 on the rear united by the T-coupling 28. A rigid tube 29 extends from the front T'-coupling' 25 through the motor between the cylinders. The front and rear assemblies are connected with the two magnetos (Figs. 3 and 4) by the flexible tubes 30, 3|, respectively. The ,assemblies are connected with suitable parts at the spark plugs-Aer example, shielding covers 32- by flexible tubes 33.

Thus broadly, there is seen to be provided a manifold having a number of separable parts which are so designed as to permit the convenient assembly thereof upon the motoras well as theconvenlent insertion therein of the insulated conductors.- Thassemblage is particularly facilitated by having portions. of the rigid conduit system mounted on opposite sides of the motor. This also permits shdrt leads to the spark plug tobe used.

The rigid tubular sections 23, 2 4, 26, 21, may be formed of any suitable metal which is a good electrical conductor and which has good abra- 3 sion resisting qualities. For example, a brass tube plated on the outside with cadmium has been found to be satisfactory. At the points where the. conductors emerge for the spark plugs- (Figs. 6, 7) the tube is pierced an'dpushed outward in smooth curvature to form nipples 34 over which the union fittings Mare secured, as by soldering. It will be seen that the end of the nipples "are disposedwell back within an annular recess of the terfere with or injure theinsulated conductors when the latter are drawn therethrough.

In order to avoid excessive corona discharge and capacitanceloss between the metal tube the manifold with insulating material. Rubber may be used and one method ofapplying it which has given good results is to placea'lining tube within the metal tube, expand it' by pres- ,sure and cement it in place;' or' the rubber may 'be applied by a plating process. Another method which hasproved satisfactory is to heat a cel lulose tube--as," for example, by soaking it in hot water-untilit softens somewhat, then to front and rear of said engine, a metallic radio shield enclosing the high tension terminals of each of said' magnetos. a shielding conduit detachably secured at one end to each of said magneto shieldsand having the other ends thereof detachably secured to one of said manifold tubes,

a metallic shield for each of said spark plugs.

and a shielding conduit detachablyconnected to each of said spark plug shields and one of said manifold tubes whereby an electric conductor connecting one of said magneto terminals .and one of said spark plus is completely manifold tubes whereby an electric conductor connecting one of said magneto terminals and one of said spark plugs is completely shielded.

6. In a dual ignition aircraft engine-of the radial type having two magnetos and a plurality of spark plugs, the combination therewith of a radio shielding ignition harness comprising rigid metallic manifold tubes mounted on the front and'rear of said engine, a plurality of metalend to one of said magnetos and at the other end to one of said manifold tubes, a metallic shield for each of said spark plugs, a plurality of metal-shielded conduits each connected atone end to' one of said spark plug shields and at the II other end thereof to one of said manifold tubes, and a plurality of electrical conductors each electrically connected to one of saidspark plugs and a terminal of one of said masnetos and each slidably extending through one of said flrsti' named conduits, one of said secondnamed conduits and at least a portion of one of said rigid manifold tubes, whereby each of said conductors is completely shielded.

- EDWIN A. ROBERTSON.

shielded conduits each detachably secured at one 10 

